The present invention relates to the production of trousers closures for fly openings, and more particularly to a method and apparatus for attaching successive fly strips to a continuous slide fastener chain.
U.S. Pat. No. 3,750,104 discloses a system for automatically attaching a plurality of fly strip pieces one after another to a continuous slide fastener chain. There, the fly strips are fed to an intermittently operable sewing machine one after another by means of feed rollers in timed relation to the intermittent operation of the sewing machine. A continuous length of fastener chain is continuously fed to the sewing machine for joining fastener chain to the fly strip pieces. This intermittent operation of the sewing machine is controlled by a photoelectric cell detector at the sewing station. The detector detects the completion of sewing of one fly strip when the trailing end of a sewn fly strip piece passes it to produce a "stop" signal not only to terminate the operation of the sewing machine but also to energize the feed rollers. Subsequently, the detector detects the arrival of the next fly strip when the leading end of the next fly strip piece passes it to produce a "start" signal to initiate the operation of the sewing machine. Since the sewing operation is halted repeatedly with this system, there is considerable waste of sewing machine on-time and only a limited rate of production of the trouser closures can be achieved.
The present invention represents a significant advance and improvement in efficiency over the prior art by providing a method and apparatus for sewing a succession of fly strips to a continuous slide fastener chain continuously, without interruption, whereby fly strip pieces are supplied successively to a sewing station, thus increasing the rate of production of trouser closures.